Machine for longitudinal grinding of wood logs.



A. N. ANDERSEN & C. VIG. MACHINE FOR LONGITUDINAL GRINDING or woon LOGS.

APPLICATION FILED JULY 14.19l5- Patented Apr. 23, 1918.

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lemmas NICOLAY ANDERSELLOF HOUGI-ISUND, EKER, AND CHRISTIAN 'VIG, or

. SKOTFOS, NORWAY. q

MACHINE FOR LONGITUDINAL- GRINDING OF WOOD LOGS.

messes.

Specification of Letters Patent. 'Patented Apr. 23 1918.

Application filed July 14, 1916. Serial No. 109,350.

To all whom it may concern:

Be it known that we, Annnns NICOLAY Axnnnsnx, a subject of the King ofNorway, residing at Houghsund, Eker, and CnIzIs'rIAN VIG, a subject ofthe King of Norway, residing at Skotfos, Norway, have invented certainnew and useful Improvements in Machines for Longitudinal Grinding ofWood Logs; and we do hereby declare the following to be a full, clear,and exact description of the invention, such as will enable othersskilled in the art to which it appertains to make and use the same,reference being had to the accompanying drawings, and to letters orfigures of reference marked thereon, which form a part of thisspecification.

The present invention relates to grinding machines for longitudinalgrinding of wood logs and the object of the invention is to provide amachine of this type in which the circularperiphery of the rotatinggrindstone will cut the fibers of the wood subjected to its grindingaction in the same direction.

The advantage of longitudinal grinding in the same direction as the woodfibers consists therein that the fiber btained are longer and finer thanthe fibers obtained in the ordinary transverse grinding processes. Thisis due to the fact, that in transverse processes the unevennesses in thegrinding surface will break up and cut the fibers so that the same arenot extracted in their whole length.

Longitudinal grinding is mostly performed on the flat side of a grindstone. It is however clear that when grindingon the fiat side of therotating stone the active parts of the grind stone will not all move inthe same direction as the fibers, as the fibers lie in a straight line,while the several parts of the grind stone move in arcs. The idealeffect cannot be obtained in this man- On the other hand when grindinglongitudinally on the cylindrical surface on the grindstone, if the woodwere first to touch the grinding surface with any point between itsends, it will be seen that the part of the wood behind this point wouldbe ground against the fibers, whereby the fibers will be broken so thatthe desired effect is not obtained. Therefore, in order to obtain thebest grinding action,tl1e' wood must first touch the grinding surfacewith its rearmost end, that is, the position of the wood with regard tothe grinding surface must be such that the fibers in the rearmost end ofthe wood form tangents to'the grinding surface.

In order to obtain this effect in grinding machines of the ordinary kindin which the grinding pockets are placed radially with regard to thegrindstone, the front surface of the pressing pistons according to thepresent invention is arranged at a certain angle to the axis of thegrinding pocket in such a manner, that, when pushed to its innermostposition, the front surface of the grinding piston will touch thegrindstone with its rearmost part taken in the direction of the movementof the grinding urface.

This object is attained by arran 'ing the pressing pistons in the.radial poo ets of the grinding machine at such an angle to the axis ofthe grinding pocket that the rearmost fibers of the wood logs as seen inthe direction of movement of the grinding surface are approximatelyparallel to the same.

On the drawing the invention i illustrated by means of a diagrammaticalsketch.

A indicates the wood logs.

B is the pressing piston, D is the pocket and C is the grindstone.

As it will be noted the pressing piston B is arranged at an angle to thewalls of the pressing pocket D, and as the wood logs A are parallel tothe pressing piston they will also lie at an angle to the walls and tothe axis of the pocket. This angle is so chosen, that the fibers at therearmost part Eof the logs subjected to the grinding action aresubstantially parallel to the grinding surface or so that the log atthis point is at least not ground against its fibers.

The invention may easily be applied on old grinding machines of theusual type by changing the pistons of the same.

Although the invention is here shown as applied on a grinding machine inwhich the wood is ground on the circumference of the grindstone, it willhowever be understood that it may also be adapted on machines where thewood is ground on the flat v ides of the grind stone.

Claim:

In a machine for longitudinally grinding wood logs, the combination witha cylindrical rotatable grind stone, of a stationary pocket for the logsto be ground having its longitudinal axis in a radius of said stone andits sides parallel to said axis, and a radially movable pressure pistonin the pocket having its forward end arranged obliquelytosaid axis andconverging toward Games nflcthianatent may be obtained for five tent thegrinding surface in the direction of movement of the latter, whereby therearmost part of the log is first moved into contact with said surface.

In testimony that we claim the foregoing as our invention, We havesigned our names in presence of two ubscribing witnesses.

ANDERS NICOLAY ANDERSEN. CHRISTIAN VIG.

Witnesses THs. BERG, M. RISER.

5 each, by addressing the Commissioner of Patents,

Washington, JR. 4?.

